CVE-2026-100658

MEDIUMCVSS 5.3/10

Last modified

CVE-2026-100658 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. Netty (io.netty:netty-codec-http) contains an unbounded per-connection queue in WebSocketServerExtensionHandler. The handler offers an entry to its per-channel validExtensions queue for every inbound HttpRequest, but polls an entry only when the application writes an HttpResponse, and the queue size is never bounded.

Description

Netty (io.netty:netty-codec-http) contains an unbounded per-connection queue in WebSocketServerExtensionHandler. The handler offers an entry to its per-channel validExtensions queue for every inbound HttpRequest, but polls an entry only when the application writes an HttpResponse, and the queue size is never bounded. A remote, unauthenticated peer can use HTTP/1.1 pipelining to send requests faster than the application produces responses — including plain non-upgrade HTTP requests to any path — causing the queue to grow without limit until the JVM exhausts heap memory and terminates with OutOfMemoryError. Because the affected handler is the base class of WebSocketServerCompressionHandler, any server that enables permessage-deflate is exposed on its plain HTTP port before any WebSocket upgrade completes and before any application-level authentication. Affected versions are 4.1.88.Final through 4.1.137.Final and 4.2.0.Final through 4.2.17.Final; the issue is fixed in 4.1.138.Final and 4.2.18.Final.

Metrics

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
nettynetty>= 4.1.88.Final, < 4.1.138.Final
nettynetty>= 4.2.0.Final, < 4.2.18.Final

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-100658?
Netty (io.netty:netty-codec-http) contains an unbounded per-connection queue in WebSocketServerExtensionHandler. The handler offers an entry to its per-channel validExtensions queue for every inbound HttpRequest, but polls an entry only when the application writes an HttpResponse, and the queue size is never bounded. A remote, unauthenticated peer can use HTTP/1.1 pipelining to send requests faster than the application produces responses — including plain non-upgrade HTTP requests to any path — causing the queue to grow without limit until the JVM exhausts heap memory and terminates with OutOfMemoryError. Because the affected handler is the base class of WebSocketServerCompressionHandler, any server that enables permessage-deflate is exposed on its plain HTTP port before any WebSocket upgrade completes and before any application-level authentication. Affected versions are 4.1.88.Final through 4.1.137.Final and 4.2.0.Final through 4.2.17.Final; the issue is fixed in 4.1.138.Final and 4.2.18.Final.
How severe is CVE-2026-100658?
CVE-2026-100658 has a CVSS score of 5.3/10 (MEDIUM severity).
How do I fix CVE-2026-100658?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST